The present invention relates to furniture and, more particularly, to a chair adapted for use in the office environment.
Many different types of office chairs are presently available. Such chairs are adapted to a wide variety of tasks and different users. An office chair may include a base structure having a height adjustable pedestal mounted on a caster assembly for easy movement. A tilt or chair control mechanism may be supported on the base, and the back of the chair may tilt with respect to the base. Chairs are also provided which include a fixed base or nontiltable support structure. Side chairs, for example, may include a so-called sled-base.
Examples of prior office chairs may be found in commonly owned U.S. Pat. No. 4,390,206 entitled SYCHROTILT CHAIR CONTROL, which issued on Jun. 28, 1984 to Faiks et al; commonly owned U.S. Pat. No. 4,494,795 entitled VARIABLE BACK ADJUSTER FOR CHAIRS, which issued on Jan. 22, 1985 to Roossien and commonly owned U.S. Pat. No. 4,744,603 entitled CHAIR SHELL WITH SELECTIVE BACK STIFFENING, which issued on May 17, 1988 to Knoblock.
Prior office chairs have included a one-piece shell which defines both the seat portion and the back portion of the chair. The shell supports the user and is a structural member. The structural shell is, however, flexible so that the seat back portion may tilt or pivot with respect to the seat portion. Various steps are taken in forming the shell to provide the desired strength and tilting action. Since the shell is a one-piece member, force is needed to deform or bend the seat back with respect to the seat portion. This force must be accommodated when designing the chair in order to achieve a particularly desired ride or feel in use. Typical chair controls or tilt mechanisms include an axle connected to a pair of back uprights. The uprights and axle are biased to an upright or first position by a torsion spring. The uprights are moved to a reclined position against the increase in force generated by the torsion spring. The back portion of the one-piece shell is mounted on or secured to the vertical uprights of the chair control mechanism. In such chairs, a cushion assembly and upholstery are secured to the front surface of the shell. The upholstery material is pulled around the edges of the shell and secured to the back surface of the shell by staples or other suitable means. A decorative, non-load bearing outer shell is attached to the inner shell to enclose the back tilt mechanism and the unfinished edges of the upholstery material.
Various problems are presented with current office chair constructions. Difficulties are presented with molding the chair shell as an integral one-piece member including a back portion and seat portion. Existing tilt mechanisms including the back uprights and existing upholstery methods necessitate the use of the outer decorative shells or covers. The cover increases the thickness of the side profile of the chair and, hence, has an effect on the chair aesthetics and cost.
A need exists for an office chair which is readily adaptable to use with a tilt mechanism and which eliminates, however, the outer decorative shells or covers and the need for the vertical uprights to support the shell back. In addition, a need exists for a chair incorporating an upholstery and cushion assembly integrated with the chair shell to provide a finished appearance while eliminating the need for a decorative outer shell or cover.